Simple MongoDB queries in Node.js

With node.js, you can build amazingly complex server-side applications that are easy to develop in a very quick time. The most important part of the development process is picking the right database architecture, and with node.js the perfect solution is MongoDB using the module mongoose.js.

Schemas

To save data to mongodb, it must be a part of a schema, defining a schema is very simple:

var mongoose = require("mongoose");

// Schema
var Channel = mongoose.model("channel", {
	name: String,
	number: Number,
});

A schema is a JavaScript object that defines how you will save your documents. The value written as String or Number signifies which type of data you will be using. A schema is basically the template of the document.

Creating a single document

To create a single document in the Schema "Channel", use the mongoose create function as so:

Channel.create(
	{
		name: "National Geographic",
		number: 208,
	},
	function (err, channel) {
		if (err) return next(err);
		return console.log(channel);
	},
);
//-> { _id: 001, name: 'National Geographic', number: 208 }

Finding a single document

To find a single document, use the findOne function along with a simple query function such as this:

Channel.findOne({ name: "National Geographic" }, function (err, channel) {
	if (err) return next(err);
	return console.log(channel);
});
//-> { _id: 001, name: 'National Geographic', number: 208 }

Find and update a single document

To find and update a single document use the findOneAndUpdate function to use a query to find a document and add the data to change:

Channel.findOneAndUpdate(
	{ name: "National Geographic" },
	{ channel: 209 },
	function (err, channel) {
		if (err) return next(err);
		return console.log(channel);
	},
);
//-> { _id: 001, name: 'National Geographic', number: 209 }

Find and remove a single document

To find and remove a single document use the findOneAndRemove document. This will use a query to find a document and then delete it from the db.

Channel.findOneAndRemove(
	{ name: "National Geographic" },
	function (err, doc, result) {
		// error: any errors that occurred
		// doc: the document before updates are applied if `new: false`, or after updates if `new = true`
		// result: [raw result from the MongoDB driver](http://mongodb.github.io/node-mongodb-native/2.0/api/Collection.html#findAndModify)
	},
);

Find a collection of documents

To find a collection of documents, use the find function:

Channel.find({}, function (err, channels) {
	if (err) return next(err);
	return console.log(channels);
});
//-> [{ _id: 001, name: 'National Geographic', number: 209 }, { _id: 002, name: 'Disney Channel', number: 290 }, { _id: 003, name: 'Disney Channel', number: 202 }]

NOTE: {} will return all documents in a particular collection, as there are no arguments.